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PLUMBING CONNECTION
WINTER 2015
The fitting of mesh as prescribed in the example
calculation compromises all other clauses on ventilation
in both parts of the Standard. It also compromises what
has been a safety requirement for decades – a clear 6mm
opening.
GAS REFRIGERATORS
The requirements for installing a gas refrigerator has
changed rather dramatically since the inception of AS/NZS
5601-2010 and 2013.
Not everyone will realise that what is required now in AS/
NZS 5601-2010 and 2013 Part 2 was in fact the normal,
safe and most efficient installation of a refrigerator in a
caravan or boat.
In all three examples shown, both vents were to atmosphere
and the top vent was always higher than the condenser/
absorption fins of the refrigerator for maximum efficiency, as it
is now shown and required in AS/NZS 5601-2013.
This type of installation was not obligatory for some
years, and caravan design changed. The upper vent of the
refrigerator compartment was lowered and was not higher
than the condenser/absorption fins depicted above (and as
now required) but very close to the same height. So the free
flow of air from outside was limited.
To prevent overheating of the refrigerator, ventilation
in some cases was introduced via bench tops over the
refrigerator compartment, or in side panels of these
supposedly sealed spaces.
There were reports of such ventilation openings allowing
combustion products (potentially including CO) into the
caravan or boat. Whether a gas refrigerator is small,
medium or large the burner usually consumes 2Mj/hr.
In one incident where flue products from a refrigerator
were spilling into an area, the CO reading was 11,000ppm, a
highly dangerous situation.
In some cases manufacturers of gas refrigerators have
recommended servicing twice yearly due to dust and dirt
build-up on the burner.
What action is required of a plumber/gasfitter who comes
across a caravan or boat refrigerator with a vent in the
bench above the compartment or in a side panel?
With the amount of information now available on the
dangers of CO, the technical regulators and educational
centres such as TAFE colleges need to provide plumbers/
gasfitters with some direction – even if it means
disconnecting the gas supply for safety.
SIGNIFICANT ANOMALY
The splitting of AS/NZS 5601-2013 into two parts has
resulted in Part 2 not having an Appendix R as does Part 1.
Both parts include an appendix that refers to “Guidelines
for gas appliance commissioning”, and both appendices are
very similar in wording.
However, a caravan can have more than one gas appliance
– oven, hotplate, space heater and even ducted heater – and
Appendix I of Part 2 does not call for all appliances to be
operating when a pressure check is being conducted.
Appendix R requires that all flued gas appliances (open
flue, power flue or balanced flue) to be operating at the same
time as all extraction fans are on.
A caravan or similar is basically a house on wheels and,
as indicated in Part 2 of the Standard’s Clause 7.4.2, it can
include a stove range-hood extractor. Let’s not forget that
some caravans can also have exhaust fans in toilets and/or
bathroom areas, let alone cooling systems with fans.
It seems that none of these additional appliances were
taken into consideration when compiling Part 2. One has to
wonder if testing has been done with all fans and appliances
operating, and with ventilation openings restricted by mesh.
We can think about what this means for plumber/
gasfitters who sign off an installation to the requirements of
AS/NZS 5601-2013 Part 2, and an incident occurs.
They would be plagued by self-recrimination for the rest of
their lives … and how much support would they get?
GAS MATTERS
ROGER LAMBIE
In some cases, to prevent overheating, ventilation was
introduced via bench tops over the refrigerator.
CONDENSER/
ABSORPTION FINS
VENTS
VENTS
VENTS